Steam heating system



Oct. 5, 1965 G. D. ARNOLD STEAM HEATING SYSTEM Filed Nov. 15, 1962United States Patent O 3,210,005 STEAM HEATING SYSTEM George D. Arnold,Peru, lind., assigner to The Dewey- Shepard Boiler Co., Inc., Peru,1nd., a corporation of Indiana Filed Nov. 13, 1962, Ser. No. 237,178 1Claim. (Cl. 237-7) This invention relates generally to steam heatingsystems of the type comprising a boiler and a radiator connectedthereto, and more particularly to a unitized steam heating systemwherein a single radiator is rigidly secured to a boiler by theinterconnecting piping so that the system may be transported andinstalled as a unit.

Conventional steam heating systems employ a number of radiators eachhaving a steam inlet at one end and a condensate outlet at the otherend, the steam inlet of each radiator being connected to a steam supplyline and the condensate outlet being connected to another line whichreturns the condensate to the boiler. Thus, in such conventional steamheating systems, each radiator forms a serially connected part of acondensing system.

The eciency of heat transfer between one `medium and another isdependent, among other things, upon the duration of the exposure of theheated medium to the heat transferring medium. In conventional steamheating systems, the steam in the radiator is continuously flowing fromthe inlet toward the outlet and thus, a given unit quantity of steam isexposed to a given incremental surface 4area of the radiator for only aninfmitesimally small period of time. The efficiency of heat transfer cantherefore be improved by exposing a given quantity of steam to a givensurface area of the heat transfer medium for a longer period of time;this improvement can be obtained however only in the absence ofcondensation of the steam which would thus cool the heat transfermedium. Thus in a steam heating system, the efficiency of heat transferwould be substantially increased by filling the radiator with steam,without continuously circulating the steam therethrough, insuringhowever that no condensation takes place in the radiator. However, suchan arrangement has been thought to be inconsistent with the closed cyclecondensing steam system required for the efficient generation ofsuperheated steam. Furthermore, formation of condensate in the radiatorhas been believed to be inherent and its removal has been thought to bedifficult.

In addition to the foregoing, conventional steam heating systems havecomprised a plurality of radiators fed from a central boiler, the systemthus necessitating extensive .and thus costly high-pressure steam linesand condensate return lines. There are many installations such as smallhomes, motels, and the like, where the expense of conventional steamheating systems is not warranted and this has lead to the development ofsmall unitized hot air space heaters, generally oil or gas fired. Suchspace heaters, while relatively inexpensive to purchase and install, donot possess the relatively high efficiency of a steam heating system.Miniature electrically tired steam boilers are now commerciallyavailable and it is therefore desirable to provi-de a unitized spaceheater incorporating a steam radiator in conjunction with such a boilerthereby gaining the increased eliciency of a steam heating system.

It is accordingly an object of the invention to provide an improvedsteam heating system.

Another object of the invention is to provide an improved steam heatingsystem having higher eciency than conventional steam heating systems.

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A further object of the invention is to provide an improved steamheating system of the closed cycle condensing type wherein steam isneither circulated through the radiator nor condensed therein.

Yet another object of the invention is to provide a unitized boiler andradiator assembly.

Further objects and advantages of my invention will become apparent byreference to the following description and the accompanying drawing, andthe features of novelty which characterize my invention will be pointedout with particularity in the claim annexed to and forming' a part ofthis specification.

The invention in its broader aspects provides a water boiler and meansfor heating the water therein thereby to generate the steam, the boilerhaving a steam outlet above the water line and a condensate return inletbelow the water line. Condensing means is provided interconnecting thesteam outlet and the condensate inlet and a radiator is provided deninga closed chamber having a steam inlet only communicating therewith. Thesteam inlet of the radiator is connected to the condensing means forreceiving steam therefrom and to be continuously filled thereby. Withthis arrangement, substantially all of the condensation takes place inthe steam inlet of the radiator means and the continuous ow of steam inthe condensing means provides an aspirating effect with the steam inletthereby removing the condensate therefrom, with the result that theradiator means is continuously lled with super-heated dry steam.

In the preferred embodiment of the invention, the radiator means isimmediately adjacent the boiler and is rigidly attached thereto by thecondensing means thereby to provide a unitized assembly.

The single ligure of the drawing schematically illustrates the improvedunitized steam heating system of the invention.

Referring now to the drawing, the steam heating system of the invention,generally indicated at 1 comprises a steam boiler assembly 2, a radiatorassembly 4 and a condensing assembly 6 which rigidly attaches theradiator 4 to the boiler 2 to provide a unitized assembly.

Boiler 2 is preferably conventionally fabricated with a verticallydisposed cylindrical shell 8 and top and bottom heads 10 and 12. It willbe understood that suitable stay bolts together with suitable lagging(not shown) will be provided, as is well known to those skilled in theart. An electrically energized immersion heater 14 is shown extendinginto the boiler 2 adjacent the bottom head 12 for heating the water 16therein. Immersion heater 14 is inclined upwardly at an angle withrespect to the bottom head 12, preferably on the order of 45, and issurrounded by a tubular sleeve 17 secured to the inner surface of theshell 8 by Welding, as at 1S. Sleeve 17 is opened at its outer end 20and also has an opening 22 formed at its inner end, thereby providingfor the circulation of water over the surface of the heater 14 from theopening 22 toward the opening 20. This circulation of water over theheating element 14 rapidly extracts heat therefrom thus preventing itfrom becoming overheated and further tends to prevent the deposit oflime or scale on the heating element. It will be understood that aplurality of such immersion heaters may be employed.

A conventional pressure control switch 24 is provided serially connectedwith the electrical leads 26 of the heater 14 and having apressure-sensing element 28 extending into the boiler for sensing thesteam pressure therein. It will be understood that leads 26 of theheating element 14 are adapted to be connected to a suitable source ofenergizing potential. It will further be readily understood that theboiler 2 will conventionally be provided with a water inlet foradmitting water to the boiler as needed,

a pressure gauge for observing the steam pressure in the boiler, and awater gauge for observing the water level in the boiler. 1t will furtherbe understood that the heater 14 when energized heats the water 16 inthe boiler 2 caus- Ving it to boil thus generating steam in the upperportion 30 of the boiler, as indicated by the dashed arrows 32.

The shell 8 of the boiler 2 is provided with a steam outlet 34 adjacentthe top head 10 and well above the water line 36 of the water 16, and acondensate return inlet 38 adjacent the bottom head 12 and well belowthe water line 36. The condensing assembly 6 comprises a steam Afeedconduit having a rst section'40 and a second section 42. The firstsection 40 of the steam feed conduit has its lower end 44 connected tothe steam outlet 34 of the boiler 2 in any suitable manner, as by elbow46 and nipple 48, the steam feed conduit section 40 extending verticallyupwardly in spaced-apart relationship with the boiler shell 8 to a pointspaced above the top head 10. Steam feed conduit section 42 has one end50 connected to the upper end 52 of the conduit section 40 in anysuitable manner, as by a union 54, makes a right angle bend, `as at 56,and extends substantially horizontally across top head of boiler 2 andvertically spaced therefrom. Steam feed conduit 42 then makes anotherright angle bend S8 and extends vertically downwardly to its end 60.

A condensate return conduit is provided having sections 62 and 64.Condensate return conduit section 62 has one end 66 connected to end 60of steam feed conduit section 42 in any suitable manner as by union 68.Condensate return conduit section 62 then makes a right angle bend 70and extends generally horizontally across top head 10 of boiler 2, beingvertically spaced thereabove and below steam feed conduit section 42, asshown. Condensate return conduit section 62 then makes another rightangle bend 72 and extends vertically downwardly to its end 74. A slightdrop is preferably provided in condensate return conduit section 62between bends 70 and 72 in order to permit the condensate to draindownwardly into condensate return conduit section 64.

Condensate return conduit section 64 has its upper end 76 connected tothe lower end 74 of conduit section 62 in any suitable manner, as byunion 78, and extends vertically downwardly in spaced-apart relationshipwith shell 8 of boiler 2. The lower end 80 of condensate return conduit64 is connected to condensate inlet 38 of boiler 2 in any suitablemanner, as by elbow 82 and nipple 84. It will be seen that steam feedconduit section 42 and its end 60, and condensate return 62 and its end66 have a larger inside diameter than steam feed conduit section 40 andcondensate return conduit section 64. It will also be seen that water 86will rise in condensate return conduit section 64 to the level 36 of thewater 16 in the boiler 2, however the water 86 in the conduit section 64will not boil by virtue of its isolation from the heater 14, and also byvirtue of the fact that relatively cooler condensate is continuouslyfalling therein.

It will be seen that steam 32 in the upper portion 30 of boiler 2 willenter steam outlet 34 and steam feed conduit section 40, as shown by thedashed arrows 88. By virtue of the larger inside diameter of conduitsections 42 and 62, a lower static pressure will exist therein whichdraws the steam toward these sections as shown by the dashed arrows 90.Conduit sections 42 and 62 are not thermally insulated and thus, as thesteam reaches end 60 of the steam feed conduit 42, it will begin tocondense as shown by the solid arrows 92. The condensate will then llowdownwardly in condensate return conduit sections 62 and 64 back to theboiler 2, the arrangement thus providing a continuous condensing cycleof steam entering condenser assembly 6 from the boiler, being condensedtherein, and being returned to the boiler as condensate.

Radiator 4 is shown as being a conventional steam radiator of the tubeand fin variety, and thus comprises Cil top and bottom headers 96, 08interconnected by a plurality of tubes which extend through fins 102, asis weil known to those skilled in the art. Headers 96, 98 respectivelyhave openings 101, 103 formed therein to which a steamline andcondensate return line are respectively connected in a conventionalsteam heating system. 1n accordance with the invention, however, opening103 in header 93 of radiator 4 is connected to opening 107 in the steamfeed conduit section 42 approximately midway between its ends 56, 58 asby a suitable nipple 104 and union 106, while the opening 101 in header96 is normally closed by a conventional bleeder valve 108. Aconventional fan is provided driven by motor 112 for blowing air acrossthe ns 102 and tubes 100, as shown by the arrows 114.

In operation, the boiler 2 is initially charged with water and is firedelectrically by immersion heater 14 which heats the water directly,thereby to boil the same. As steam is generate-d, it expands to ll thespace 30 above the water line 36 in the boiler 2 and expands into thesteam feed conduit 40, 42 and into the closed chamber defined by thetubes 100 and headers 96, 98 of the radiator 4; bleeder valve 10S isactuated initially in order to bleed air from the system as it lls withsteam. As the steam pressure increases, the temperature of the steamincreases proportionally thereby to provide superheated steam. The steamexpanding into the steam feed conduits 40, 42 also expands into thecondensate return conduit 62 where it begins to condense, the condensatereturning to the boiler by gravity, thus initiating the condensingcycle. When the initial steam pressure at opening 103 in header 98 ofradiator 4 equals that in steam feed conduit 42 at opening 107, nofurther steam will enter the radiator and all of the steam generatedwill momentarily be circulating in the condensing circuit.

lt will now be seen that initially, a body of steam is injected into theclosed compartment defined by the tubes and headers of the radiator 4,which steam remains, without flow through the radiator, continuallyexposed to the heat transferring elements, i.e., the interior walls ofthe tubes 100. As heat transfer takes place, however, the temperature ofthe steam within the radiator 4 is reduced thus reducing its pressureand providing some condensation, which however it is believed takesplace in the short neck section formed by nipple 104 and union 106. Assoon as the pressure within the radiator 4 is reduced below thatprevailing at opening 107 on steam feed conduit section 42, more steamwill enter radiator 4 to equalize the steam pressure, the flow of steamin the steam feed conduit 42 passing opening 107 therein which isconnected to opening 103 in header 98 of radiator 4 providing anaspirating action which removes the condensate from the neck section,the thus aspirated condensate being entrained in the steam flowing inthe steam feed conduit 42.

It will be seen that since a given quantity of steam remains in radiator4 for a substantial period of time, the heat transfer to the tubes 100is considerably more efcient than would be the case with the steamrapidly flowing therethrough. Further, it is seen that any tendency forthe steam pressure within the radiator to drop as a result `of thetendency to lower its temperature due to the heat transfer isimmediately accompanied by injection of a small quantity of new steamthus maintaining the temperature of steam in the radiator at essentiallythat prevailing at opening 107 in steam feed conduit section 42, whichin turn will be only slightly less than that prevailing in the boiler 2.The steam in radiator 4 thus remains continuously superheated, therebeing no condensate forming on the walls of the tubes 100 to cool thesame.

Directly connecting radiator 4 to the boiler 2, or con necting it to apoint on the condensing system 6 at which condensation has already begunto take place will result in the boiler priming or lling up the radiatorwith saturated steam or condensate, thus greatly lowering the eiciencyof the system.

In a specific embodiment of the invention having a boiler 2accommodating approximately 11/2 gallons of Water, conduit sections 40,64 and 84 were formed of 1 inch (inside diameter) pipe and conduitsections 42 and 62 were formed of one and one quarter (1%) inch pipe,the short neck section extending from opening 107 in conduit section 42to opening 103 in radiator header 98 likewise having an inside diameterof one and one quarter (1%) inches. In this embodiment, conduit section42 was disposed six and one-half (6l/2) inches above top head 10 ofboiler 2 and had an overall length of fteen and one-quarter inches,there being seven and three-quarters (7%) inches between bend 56 andopening 107 and 6 inches between opening 107 and bend 58. Conduitsection 62 was disposed two (2) inches below conduit section 42 and hadan overall length of sixteen and three-quarter (163/4) inches with a onequarter (1/4) inch drop between bends 70 and 72.

Radiator 4 had a heating surface of .80 square foot and was connected toconduit section 42 as closely as possible, i.e., the bottom surface ofheader 98 being approximately one and one-half (l1/z) inches aboveconduit section 42 in the specific embodiment. With this arrangement andwith the pressure control switch 24, 28 set to provide a boiler pressureof 85 lbs. per square inch, superheated steam at 320 F. is provided inboiler 2, the temperature of conduit section 42 at opening 107 beingapproximately 310 F. and the temperature of the exterior of tubes 100 ofthe radiator 4 adjacent the top header 96 having been found to be 292F.; this exterior temperature of tubes 100 clearly indicates that nocondensation is taking place therein. With fan 110 providing air flow atthe rate of 500 to 900 cubic feet per minute, the temperature of the airleaving radiator 4 immediately adjacent the side thereof remote from fan110 was found to be 250 F. at a pressure of 6 inches of mercury, withthe heating element 14 injecting 37,000 B.t.u. heat units into the waterin the boiler.

It will be seen that the radiator 4 is supported immediately above andrigidly connected to the boiler 2 by the condensing assembly 6 therebyproviding a compact, unitized, readily transportable assembly. It willbe readily understood that conventional duct Work may be connected tothe radiator 4, thus making the system suited for use as a furnace formotel rooms, smaller homes, and the like, the system providing thedesirable features of both steam and electric heating.

While I have illustrated and described a specific embodiment of myinvention, further modifications and improvements will occur to thoseskilled in the art and I desire therefore in the appended claim to coverall modications which do not depart from the spirit and scope of myinvention.

What is claimed is:

A steam heating system comprising:

(a) a steam boiler accommodating Water at all times,

(1) said boiler having a steam youtlet above the water line therein anda condensate return inlet below the water line;

(b) immersion heating means in said boiler below the water line forheating said water to generate steam,

(c) steam pressure control means coupled to said heating means,

(1) said heating means and control means being proportioned and arrangedcontinuously to provide high pressure superheated steam in said boiler;

(d) a closed cycle steam condensing line having one end connected tosaid steam outlet and its other end connected to said condensate inletfor continuously circulating steam and condensate therebetween,

( 1) a rst portion of said steam line adjacent said steam outlet havingsuperheated Steam only therein and a second portion connecting saidfirst portion to said condensate inlet having condensate therein,

(2) said first portion of said steam line including a first straightsection;

(e) a single radiator defining a closed chamber and having a singlecommon steam inlet and condensate drain opening communicating therewith;

(f) and a T-connection of minimum length coupling said radiator openingand said first section of said steam line intermediate its ends forreceiving superheated steam therefrom and for continuously filling saidchamber with superheated steam,

(g) said first section of said steam line and said connection forming anaspirator whereby the flow of steam in said steam line removescondensate from said radiator,

(h) said T-connection being the sole connection to said steam linebetween said steam outlet and condensate inlet;

(i) said boiler, said heating means, and said first portion of saidsteam line being proportioned continuously to supply superheated steamto said T-connection and said radiator during dissipation of heattherefrom.

References Cited by the Examiner UNITED STATES PATENTS EDWARD I.MICHAEL, Primary Examiner.

FREDERICK L. MATTESON, JR., JAMES W. WEST- HAVER, Examiners,

